Battery Equivalents and Replacements

LiPo 4S Battery 101: All About LiPo 4S Batteries

Lithium Polymer (LiPo or Li-Po) rechargeable batteries consisting of 4 cells connected in series are most commonly known as LiPo 4S batteries and are very popular high-discharge batteries used in various remote-controlled (RC) toys, RC trucks, and other RC vehicles, RC planes, in FPV applications and other applications where a lightweight power source is required that is able to provide plenty of power.

Lithium Polymer 4S batteries, like all other Lithium Polymer batteries, feature electrolytes in the form of polymer gel with graphic anode and cathode in the form of a Lithium Cobalt Oxide (LiCoO2) or some similar material and are often soft to touch. However, some manufacturers offer their models in hard cases in order to protect the batteries from mechanical impacts and vibrations, but also in order to improve the performances, by ensuring more constant contact between battery plates and electrolytes.

Published: October 12, 2021.

zeee 4s 7000mah 100c battery w300px

LiPo 4S Batteries Features and Specifications

LiPo 4S batteries consist of 4 LiPo cells connected in series, hence the "4S" as part of their labels.

Each cell features a nominal voltage of 3.6-3.7 volts (mostly 3.7 volts), a maximum charging voltage of ~4.2 volts, and a cutoff voltage around 3.2 volts.

Like all lithium batteries, LiPo 4S batteries tolerate deep discharges very well, but since they rarely feature Battery Management System (BMS) which will protect them from high/low temperatures, high/low voltages, high/low currents, LiPo 4S batteries may be sensitive to unwanted events, including overcharging, over-discharging, short-circuit and similar.

LiPo 4S batteries thus feature a nominal voltage of 14.8 volts and capacity usually in the range of 750 mAh to 10+Ah.

Maximum discharge current is expressed using the battery capacity, and is usually in the 30-100C, with some models being able to deliver even more Amps, at least for a very short time.

For example, the very popular Zeee 4S 100C 14.8V 9000mAh LiPo battery (Amazon link, link opens in the new window) is able to provide up to 900(!) Amps, at least for a very short time.

The output current of such batteries is often limited by the wires and connectors, despite having thick discharge wires and connectors (often gold plated) optimized for strong currents - for short, these batteries are able to provide insane levels of power, and although they are intended to power toys, among other applications, these batteries are anything but toys!

goldbat 4s 1500mah 100c

LiPo 4S batteries feature two sets of cables, charging cables and discharging cables.

Discharging cables usually feature XT60, EC5, or similar plugs, while charging cables usually feature a JST-XH plug, which allows not only charging of the battery but also cell balancing.

Note: if the cells are not periodically balanced, charging the battery to 16.8 volts (4 x 4.2 volts) would mean that some of the cells are overcharged (above 4.2 volts) and some cells are not charged to their full charge - such charging can not only shorten the battery lifetime, but also cause the battery to overheat, or even burst to flames or even explode!

So, when charging LiPo 4S batteries, a balance LiPo battery charger is highly recommended.

As part of their maintenance, it is also recommended to periodically discharge LiPo batteries in a controlled environment - if possible, go for a good balance LiPo battery charger that also features a battery discharge feature.

Note: when new batteries arrive, it is a good practice to fully charge/discharge them few times in controlled conditions, using relatively low discharge currents, gradually increasing their DoD% (for example, down to 25% DoD, 50% DoD and 75% DoD). Although LiPo 4S batteries may provide discharge currents up to or even more than 100C, recommended maximum charging currents are usually in the 0.5-1.0C range!

Since LiPo batteries are in general more sensitive than Lithium Iron Phosphate (LiFePO4) batteries, it is recommended to never leave LiPo batteries unattended while they are being charged.

Also, it is recommended to store and transport them in fireproof bags - better safe than sorry.

lipo 4s battery mLong Story Short: If You are looking for a new LiPo 4S battery, be sure to check the physical dimensions of the old battery, its connectors, capacity, current rating and choose the battery that features the same physical dimensions and connectors, and the same or better capacity and current rating.

Always choose the batteries from reputable brands, charge them with professional balance battery chargers and keep them in fireproof bags. Again, they are often used for powering various RC toys, but the batteries themselves are not toys.